The proliferation of cloud-connected electronic devices has enabled the widespread availability of documents, such as books, in electronic format. In addition, these devices have also allowed users to access a variety of content items, such as videos on a variety of subjects.
However, despite the wide spread availability of content items on a variety of subjects, many of these electronic documents are just digital versions of the corresponding printed document and do not incorporate any of the available content items. For example, e-books typically do not include any more content than their printed counterparts.
Incorporating content items into the electronic documents may be particularly useful for electronic textbooks. Research has shown that students comprehend lessons better when the information is presented in a variety of different formats. For example, a user who reads a textbook chapter on a subject may recall more of the information presented in the chapter when it is followed or proceeded by a video that repeats some or all of the information presented in the chapter.
However, determining which content items to associate with a document is time consuming. For example, a user may have to both read the textbook and later view candidate content items to determine which content items are germane to a particular document or sections of the document. The user may then further have to determine an optimal location to place the content item in the document.